In the main trend of energy conservation and emission reduction, the efficiency of a voltage converting device is also continuously improved. Many line topologies are emerging. In an application field represented by an IT industry, market demands for power-off parts are very large, and currently, are still occupied by a traditional “atypical tandem” power-off protection device (UPS and charger). Users and the markets turn a blind eye to the fact that the function utilization rate of “atypical tandem” UPS is lower than the probability of AC power off, and do not know the huge waste caused actually. A typical application form is IDC room which frequently has UPS redundant power supply protection systems with hundreds of KVA, construction cost ranging from millions of RMB to tens of millions of RMB, and waste of millions of kilowatt hours of electric energy per year.
Currently, digital equipment, such as computers, security monitoring systems, etc. also needs to select a double-input voltage converting device generally so as to maintain uninterrupted operation of equipment and prevent data loss caused by power failure.